At least 22 dead in head-on train crash in southern Italy

This aerial handout photo shows what is left of two commuters trains after their head-on collision in the southern region of Puglia, Tuesday, July 12, 2016. At least 10 people died and several others are reported injured. (Italian Firefighter Press Office via AP)A damaged passenger train is seen after a collision with another in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/handout via ReutersTwo passenger trains are seen after a collision in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersTwo passenger trains are seen after a collision in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersTwo passenger trains are seen after a collision in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersItalian firefighters Vigili del Fuoco inspect the wreckage of two commuter trains after their head-on collision in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Italian Firefighter Press Office via AP)The wreckage of a crumpled wagon at the scene of a train accident after two commuter trains collided head-on in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Italian Firefighter Press Office via AP)Italian firefighters Vigili del Fuoco respond to the scene of a train accident after two commuter trains collided head-on in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Italian Firefighter Press Office via AP)Two passenger trains are seen after a collision in the middle of an olive grove in the southern village of Corato, near Bari, Italy Italian Firefighters/Handout via Reuters

At least 22 people have died after two Italian commuter trains collided head-on in the southern region of Puglia, officials said.

Scores more were injured and at least two passengers were pulled alive from the crumpled wreckage as the rescue operation ground on in the scorching heat.

Railway police commander Giancarlo Conticchio told Sky TG24 said that the number of dead was 22 with 43 people injured, adding that the final toll could still be higher.

"Surely one of the two trains shouldn't have been there. And surely there was an error. We need to determine the cause of the error," Mr Conticchio said.

Another official stressed the final toll would not be known until the train cars had been pulled apart; a giant crane arrived at the scene to remove the mangled debris.

The two trains, each with four cars, collided head-on in an olive grove on flat terrain between the towns of Andria and Corato on a line with just a single track. The accident occurred around 11.30am local time, some 30 miles north-west of the Puglia regional capital, Bari.

Firefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersTwo passenger trains are seen after a collision in the middle of an olive grove in the southern village of Corato, near Bari, Italy Italian Firefighters/Handout via ReutersTwo passenger trains are seen after a collision in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersFirefighters work at the site where two passenger trains collided in the middle of an olive grove in the southern village of Corato, near Bari, Italy, in this handout picture released by Italian Firefighters July 12, 2016. Italian Firefighters/Handout via ReutersThis aerial handout photo shows what is left of two commuters trains after their head-on collision in the southern region of Puglia, Tuesday, July 12, 2016. At least 10 people died and several others are reported injured. (Italian Firefighter Press Office via AP)Italian firefighters Vigili del Fuoco inspect the wreckage of two commuter trains after their head-on collision in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Italian Firefighter Press Office via AP)The wreckage of a crumpled wagon at the scene of a train accident after two commuter trains collided head-on in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Italian Firefighter Press Office via AP)Italian firefighters Vigili del Fuoco respond to the scene of a train accident after two commuter trains collided head-on in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Italian Firefighter Press Office via AP)

"It's a disaster as if an airplane fell," Corato mayor Massimo Mazzilli said on his Facebook page, where he posted photos of the crash.

Italian premier Matteo Renzi pledged a thorough investigation and returned to Rome from Milan to monitor the situation. His transport minister, Graziano Delrio, as well as local prosecutors were at the scene.

"We must begin to understand the causes of this tragedy that has saddened the whole country," Mr Delrio said at the site, announcing a commission of inquiry. "The crash was certainly violent. Extremely violent."

The cars clearly slammed into one another: They rested crumpled together like an accordion, off the tracks at sharp angles. News reports said rescue workers pulled a child alive from the rubble.

Riccardo Zingaro, the chief of the local police in Andria, told Sky it was "a great tragedy". Some rescue workers seemed overwhelmed by the scene and the heat.

"The impact was significant, and we are now verifying the consequences," said Giovanni De Siervo of Italy's civil protection service.

A field hospital was set up in the nearby fields to treat the numerous injured, who were also being transported to hospitals.

"Some of the cars are completely crumpled and the rescuers are extracting people from the metal, many of them injured," Mr Zingaro told ANSA at the scene.

Mr Renzi said the train crash "is a moment of tears" and pledged not to stop investigating until a cause was determined.

The trains were operated by a private, Bari-based rail company, Ferrotramviaria, that connects the city of Bari with Puglia towns to the north and the airport.

Ferrotramviaria's website said its fleet comprises 21 electric trains, most with four cars each. The line serves mostly students and commuters.

In a phone interview with state TV, Ferrotramviaria director general Massimo Nitti said the dynamics of what went wrong are still to be determined, but it is clear "one of the trains wasn't supposed to be there" at the same time as the other.